(a) A person who uses a firearm while committing a felony shall be imprisoned for not more than ten (10) years in addition to the punishment for the felony. For a second or subsequent conviction under this section a person shall be imprisoned for not more than twenty (20) years in addition to the punishment for the felony.
(b) Subsection (a) of this section does not apply to those felonies which include as an element of the crime the use or possession of a deadly weapon.